Word has it that when Sony's first 'Downloadable Content' (DLC) pack for Gran Turismo 6 becomes available on December 12, there will be a couple of special new German models included.

Sony has already confirmed the new M4 coupe will be offered in the first DLC round, but now BMW is understood to locked in an official unveiling for the same date, ahead of a world premiere at the Detroit Motor Show.

Today, the carmaker has released a new short teaser video not only for the M4 coupe, but also for its sedan sibling - which will, of course, continue with the legendary M3 name.

BMW has not been shy on dishing up the important details for the new M twins, revealing in September that both cars will feature a turbocharged six-cylinder engine delivering around 316kW and "well over" 500Nm of torque.

Little else is known however - acceleration figures remain a secret for now - although it is believed the M4 will bring a sub-1400kg kerb weight to the party.